This application claims the priority of Korean Patent Application No. 10-2003-0029130 filed on May 7, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
1. Field
This disclosure teaches techniques related to an RF transceiver apparatus including a receiver unit with a low noise amplifier (LNA) and a filter, and a transmitter unit with a power amplifier and a filter, and a UWB signal transceiving method. More particularly, the teachings relate to techniques for overcoming interference which may be produced in a frequency band overlapped with a frequency band of radio communications currently used in an RF transceiver apparatus using ultra wide band (UWB) technology.
2. Description of the Related Art
FIG. 1 is a schematic diagram showing a related art radio frequency (RF) transceiver apparatus. As shown in FIG. 1, when the RF system is in receive mode, a switch is connected to an input terminal of a low noise amplifier (LNA). RF signals input to an antenna connected to the LNA are transmitted to a filter via the LNA. The RF signals are transmitted further to a down converter via the filter when a carrier is used with the system. In case if no carrier is used, the RF signals are transmitted directly to a demodulator.
When the RF system is in transmit mode, the switch is connected to an output terminal of a power amplifier. When a carrier is used, the signals after passing through an up converter and a filter are amplified in the power amplifier. They are then transmitted, as electrical energy, into space through the antenna. When a carrier is not used, modulated signals are amplified in the power amplifier after passing through the filter. They are then transmitted through the antenna.
Increasingly, wireless communication system available for use in a number of wireless local area network (WLAN) and wireless personal area network (WPAN) require data transmission rates as high as those used in wired communication system. Such a need is met only if a UWB (ultra wide band) is used. UWB has a data rate that is the highest among currently used WLAN or WPAN wireless communication systems. Since a bandwidth of at most 200 to 300 MHz is generally employed in such a related art RF transceiver apparatus, it is not so difficult to construct the LNA, the power amplifier and the filter. Further, since a specific predetermined narrow band is used, the band rarely interferes with the other systems.
However, several problems are encountered if an UWB system having a bandwidth of several hundred MHz or GHz is used. An acute problem in using the UWB is that the UWB uses predetermined frequency bands that are already used by other commercial wireless communication systems. There is a strong possibility that a malfunction in the UWB system may be produced in a specific frequency band overlaps with that used by the other radio communication systems, because signal power thereof is low and receiver sensitivity is also accordingly low. Further, since the LNA, the power amplifier, the filter, and the like, which are used in a UWB system, should cover the broad bandwidth, they cannot exhibit good performance throughout the entire frequency band of interest. As a result, some problems such as signal distortion may occur in some frequencies.
Therefore, there is a need for an apparatus that can cause a UWB system not to interfere with, or not to be interfered by, wireless communication systems operating adjacent to the UWB system.